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Finding the Fourth Proportional to 682.10, 1,021.80 and 393.20

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Solution

The fourth proportional to 682.10, 1,021.80 and 393.20 is: 589.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    682.10 : 1,021.80 = 393.20 : x
  2. Step 2: Convert to fraction form
    682.10/1,021.80 = 393.20/x
  3. Step 3: Cross multiply
    682.10x = 1,021.80 × 393.20
  4. Step 4: Simplify right side
    682.10x = 401,771.76
  5. Step 5: Solve for x
    x = 401,771.76/682.10
  6. Step 6: Final answer
    x = 589.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.